Grinding Tool and Method for Producing a Grinding Tool

ABSTRACT

A grinding tool has a main body having at least one fiber ply embedded in a binder. An abrasive layer is arranged on the main body. The at least one fiber ply is arranged in the binder in a partially movable manner. As a result, a relative movement that ensures high vibration and noise damping is achieved within the main body and within the at least one fiber ply.

FIELD OF THE INVENTION

The invention relates to a grinding tool and to a method for producing agrinding tool.

BACKGROUND OF THE INVENTION

A roughing grinding wheel is known from EP 1 543 923 A1. The roughinggrinding wheel has two layers of bonded abrasive particles, the layersbeing reinforced by external reinforcements and internal reinforcements.An annular separating layer is arranged between the innerreinforcements. The separating layer is formed by intermediate layersthat rest against one another and are composed of paper or plastic film,for example. The separating layer reduces the amplitude of the vibrationduring grinding without making the structure of the abrasive grit boundby means of binder softer and without increasing abrasion.

SUMMARY OF THE INVENTION

It is an underlying object of the invention to provide a grinding toolwhich is simple to produce and can be used in a flexible manner andwhich has high vibration and noise damping combined with high cuttingperformance and a long life.

This object is achieved by means of a grinding tool comprising a mainbody having a binder, at least one fiber ply embedded in the binder, andan abrasive layer, wherein the at least one fiber ply is arranged in thebinder in a partially movable manner. By virtue of the fact that the atleast one fiber ply is arranged in the binder in a partially movablemanner, free relative movement is achieved within the at least one fiberply during grinding, with the result that the main body achieves highvibration and noise damping. To achieve the free relative movementwithin the at least one fiber ply, the amount of binder used in theproduction of the main body is, on the one hand, sufficiently large toensure that the main body has adequate stability and, on the other hand,sufficiently small to ensure that the at least one fiber ply is notbonded continuously and/or over its entire surface to the binder. The atleast one fiber ply is embedded in the binder in such a way that a firstregion of the at least one fiber ply is firmly connected to the binderand a second region of the at least one fiber ply is movable relative tothe binder and the first region. The at least one fiber ply preferablyhas at least one yarn. The at least one yam is arranged in the binder ina partially movable manner. The at least one yarn preferably has a firstyarn portion, which is arranged in such a way as to be immovablerelative to the binder, and at least one second yarn portion, which isarranged in a movable manner relative to the binder. The second yarnportion is, in particular, arranged in a movable manner relative to thefirst yarn portion. The binder is preferably a resin and/or an adhesive.The binder is preferably a thermoset, in particular phenolic resin orepoxy resin.

The main body and thus the grinding tool can be produced in any desiredshape, providing great flexibility in the use of the grinding tool. Thevibration- and noise-damping design of the main body does not have adisadvantageous effect on the abrasive layer. The abrasive layer isarranged directly and/or indirectly on the main body, which ensures highstability and a long life by means of the at least one fiber ply. Thegrinding tool is furthermore simple to produce.

The abrasive layer is designed to match the intended use of the grindingtool. The abrasive layer preferably comprises an abrasive particle layerwhich is applied electrostatically to the main body. The abrasiveparticles of the abrasive particle layer are, in particular, secured bymeans of an adhesive agent on a surface of the main body. In particular,the abrasive particles are at least partially aligned with the main bodyand/or with respect to one another. The abrasive particles have ageometrically determined and/or a geometrically indeterminate shape. Theabrasive particles comprise at least one material selected from thegroup comprising ceramics, corundum, in particular zirconia corundum,diamond, cubic crystalline boron nitride (CBN), silicon carbide, andtungsten carbide. The abrasive particles can be applied in a singlelayer or in multiple layers. In the case where a plurality of abrasiveparticle layers are formed, an adhesive agent is applied to therespective abrasive particle layer situated underneath, and thesubsequent abrasive particle layer is applied. The abrasive particlelayer is secured on the main body or a supporting layer, which isconnected to the main body. The abrasive layer comprises, in particular,a base binding, abrasive particles, and a top binding. The abrasiveparticles can be introduced at different base binding levels or appliedto the main body.

The abrasive layer comprises, in particular, an abrasive fleece. Theabrasive fleece is secured by means of an adhesive agent, for example,on a surface of the main body. The abrasive layer furthermore comprisesan abrasive on a backing. The abrasive on a backing comprises, inparticular, a supporting layer on which abrasive particles are secured.The abrasive on a backing is designed as abrasive flaps, for example.The abrasive particles used, in particular diamond abrasive particles,can be used on a metal backing.

The main body preferably has a hub or a shaft for clamping and rotarydriving of the grinding tool. The grinding tool is, in particular, agrinding wheel.

A grinding tool configured such that each fiber ply comprises aplurality of yarns that are embedded in the binder in a partiallymovable manner relative to one another, ensures high vibration and noisedamping. By virtue of the fact that the yarns of the respective fiberply are arranged in a partially movable manner relative to one anotherand to the binder, a movement of the yarns relative to one another andthus a relative movement within the respective fiber ply are achieved.The main body preferably has a plurality of fiber plies, the respectiveyams of which are embedded in the binder in a partially movable mannerrelative to one another.

A grinding tool configured such that the main body comprises a pluralityof fiber plies that are embedded in the binder and are movable relativeto one another in some region or regions, ensures high vibration andnoise damping. The fiber plies are preferably embedded one above theother in the binder. By virtue of the fact that the fiber plies aremovable relative to one another in some region or regions, a relativemovement within the respective fiber ply, on the one hand, and arelative movement between the fiber plies, on the other hand, areachieved. By virtue of the multi-ply construction, the main bodyfurthermore has a high stability or strength and ensures a long life ofthe grinding tool. The fiber plies comprise at least one first region,which is connected firmly to the binder, and at least one second region,which is movable relative to the binder and to the at least one firstregion.

A grinding tool configured such that the main body comprises a pluralityof fiber plies having a plurality of yarns, and the yarns are embeddedin the binder in a partially movable manner relative to one another,ensures high vibration and noise damping. In particular, the fiber pliesare arranged one above the other. By virtue of the fact that the yamsare arranged in a partially movable manner relative to one another andto the binder, a relative movement between the fiber plies and/or arelative movement within the respective fiber ply are/is achieved.

A grinding tool configured such that the at least one fiber plycomprises at least one woven fabric and/or at least one non-crimpfabric, ensures high vibration and noise damping and a long life. Byvirtue of the fact that the at least one fiber ply comprises at leastone woven fabric and/or at least one non-crimp fabric, a vibration- andnoise-damping relative movement is achieved in a simple manner withinthe main body. At the same time, the main body has a high stability andaccordingly makes possible a long life. The at least one woven fabricand/or the at least one non-crimp fabric comprises at least one yarn, inparticular a plurality of yarns. In particular, the at least one wovenfabric comprises warp yarns and weft yarns. The at least one yarncomprises a first yam portion, which is immovable relative to thebinder, and at least one second yarn portion, which is movable relativeto the binder and relative to the first yarn portion. For example, theat least one woven fabric has a twill weave. The twill weave fabricallows simple movements of the warp yarns and/or of the weft yarnswithin the woven fabric and thus relative movement in order to achievehigh vibration and noise damping. The at least one woven fabric and/orthe at least one non-crimp fabric are/is preferably produced from glassfibers, carbon fibers, cotton and/or polyester.

A grinding tool configured such that the main body comprises a number Nof fiber plies, wherein: 1≤N≤12, in particular 2≤N≤10, and in particular4≤N≤8, ensures high vibration and noise damping in combination with along life. The more fiber plies the main body comprises, the higher thedegree of relative movement that can be achieved within the main bodyis. Furthermore, the stability of the main body increases with thenumber of fiber plies, thereby ensuring a long life. Conversely, theoutlay on production increases with the number of fiber plies, andtherefore there is an optimum range for the number of fiber plies.

A grinding tool configured such that, for a ratio M of a mass m_(B) ofthe binder to a mass m_(F) of the at least one fiber ply, the followingapplies: 1/25≤M≤½, in particular 1/20≤M≤⅓, in particular 1/15≤M≤¼, andin particular 1/12≤M≤⅙, ensures high vibration and noise damping incombination with a long life. The following applies to the ratio M:M=m_(B)/m_(F), where mB denotes the mass of the binder, and m_(F)denotes the mass of the at least one fiber ply. On the one hand, theratio M ensures that the main body has sufficient stability and, inparticular, is not delaminated or does not fold over in an unwantedmanner during grinding. On the other hand, the ratio M ensures that theat least one fiber ply is not connected fully or over the full area withthe binder and that there is no continuous bond with the binder, thusensuring sufficient relative movement within the main body. The degreeof relative movement within the main body is all the greater, thesmaller the ratio M. Conversely, the degree of stability is all thegreater, the higher the ratio M.

A grinding tool configured such that the main body comprises dampingparticles, in particular rubber particles and/or foam particles, ensureshigh vibration and noise damping. The damping particles are incorporatedinto the main body as a damping additive during production. On the onehand, the damping particles themselves have vibration- and noise-dampingproperties. On the other hand, the damping particles prevent the atleast one fiber ply from being connected fully or over the full area tothe binder.

A grinding tool configured such that the binder is an organic adhesive,in particular phenolic resin, epoxy resin and/or natural rubber, ensureshigh vibration and noise damping in combination with a long life. Thebinder ensures that the at least one fiber ply is reinforced in someregion or regions, and the binder itself preferably has dampingproperties. The binder is a mixture of phenolic resin and naturalrubber, for example.

A grinding tool configured such that the main body is of curved design,can be used in a flexible way and ensures high vibration and noisedamping in combination with high cutting performance and a long life.The main body is of curved design in at least some section or sectionsof a working region. In the working region, the abrasive layer isarranged on the main body. The abrasive layer is of curved design in atleast some section or sections of the working region. This enables thegrinding tool to be used in a flexible way, e.g. for fillet weldmachining and/or for edge machining. The main body and/or the abrasivelayer is of curved design, particularly in a radial direction and/or ina circumferential direction relative to an axis of rotation of thegrinding tool. The curved design is concave and/or convex. The abrasivelayer preferably comprises an abrasive particle layer, which is secureddirectly on a surface of the main body by means of an adhesive agent. Byvirtue of the curved design of the main body, forces that arise duringgrinding can be transferred efficiently to the main body and dampedthere, with the result that the grinding tool exhibits high vibrationand noise damping. By virtue of the fact that the curved main bodyallows a curved design of the abrasive layer, the cutting performance indifferent applications is high.

A grinding tool comprising a supporting layer, which is connected to themain body and on which the abrasive layer is arranged, can be used in aflexible way and ensures high vibration and noise damping in combinationwith high cutting performance and a long life. The supporting layerserves as an intermediate layer between the main body and the abrasivelayer and has advantageous properties, depending on the desired use. Thesupporting layer is preferably connected monolithically to the mainbody. In particular, the supporting layer does not form any undercutswith the main body. Abrasive particles are preferably appliedimmediately or directly to the supporting layer to form the abrasivelayer. The abrasive particles are secured by means of an adhesive agenton a surface of the supporting layer, for example. The abrasiveparticles are secured by electrostatic application on the surface of thesupporting layer, for example. The supporting layer is preferably formedfrom a metallic material.

A grinding tool configured such that the abrasive layer is shapedthree-dimensionally, ensures flexible usage capability in combinationwith high cutting performance. The three-dimensional shape of theabrasive layer is dependent on the desired use, and therefore highcutting performance and a long life are achieved for the desired use.The abrasive layer is curved, for example, and/or is aligned in severalplanes relative to one another, e.g. in planes that extend obliquelyrelative to one another. The abrasive layer is preferably of curveddesign in two directions extending perpendicularly to one another, e.g.in a radial direction and in a circumferential direction relative to theaxis of rotation of the grinding tool. A curved design allows filletweld machining and/or edge machining, for example. By means of planesextending obliquely to one another, the abrasive layer forms a chamferwhich allows roughing or surface machining. The abrasive layer ispreferably secured by means of an adhesive agent directly on a surfaceof the main body or on a surface of a supporting layer connected to themain body. In particular, the abrasive layer is produced byelectrostatic application of abrasive particles.

It is furthermore a desirable outcome of the invention to provide amethod for simple production of a grinding tool which can be used in aflexible manner and which has high vibration and noise damping combinedwith high cutting performance and a long life.

This object is achieved by means of a method for producing a grindingtool having the following steps:

-   -   preparing at least one fiber ply and a binder,    -   producing a main body by heating and then cooling the binder,        wherein the at least one fiber ply is arranged in a partially        movable manner in the binder after cooling, and    -   forming an abrasive layer.

The advantages of the method according to the invention correspond tothe advantages of the grinding tool according to the invention that havealready been described. In particular, the method can also be refined bymeans of features of the grinding tool, in particular by means of afeature according to the invention.

A method configured such that a plurality of fiber plies are used toproduce the main body, ensures the production of the grinding tool withhigh vibration and noise damping in combination with a long life. Thefiber plies are arranged one above the other and are connected to oneanother in such a way, by heating and then cooling the binder, that, onthe one hand, the main body has sufficient stability and strength and,on the other hand, that a relative movement is achieved within the mainbody.

A method a configured such that the heating of the binder takes placeunder pressure, ensures the production of the grinding tool with highvibration and noise damping in combination with a long life. By virtueof the fact that the at least one fiber ply, preferably the plurality offiber plies, is/are compressed during the heating of the small quantityof binder, the binder is distributed sufficiently to ensure that themain body retains a sufficient strength. By virtue of the small quantityof binder, however, no continuous or full-area bond is formed within therespective fiber ply and/or between the fiber plies, thus ensuring thata relative movement is achieved within the main body during grinding.The cooling of the binder preferably also takes place under pressure.

A method configured such that preparation takes place in such a way thatthe at least one fiber ply is provided with the binder on one sideand/or in some region or regions on two sides, ensures simple productionof the grinding tool with high vibration and noise damping incombination with a long life. By virtue of the fact that the at leastone fiber ply is provided with the binder on only one side and/or onlyin some region or regions on two sides, no continuous or full-area bondis formed with the binder during the production of the main body. Therespective fiber ply is impregnated with the binder, for example. Theimpregnated fiber ply has been produced in an upstream production step,for example. During the production of the main body, a plurality offiber plies provided with binder and optionally at least one fiber plywithout binder are preferably arranged one above the other.

A method configured such that preparation takes place in such a way thata first fiber ply without binder is arranged adjacent to a second fiberply provided with binder, ensures simple production of the grinding toolwith high vibration and noise damping in combination with a long life.By virtue of the fact that the fiber plies with and without the binderare arranged adjacent to one another, no continuous or full-area bondwith the binder is achieved during the production of the main body. Thedesired relative movement within the main body is thereby made possible.A plurality of first fiber plies and a plurality of second fiber pliesare preferably arranged alternately one above the other. The respectivesecond fiber ply is preferably provided with the binder on one side oron two sides. The respective second fiber ply is impregnated with thebinder, for example.

A method configured such that preparation takes place in such a way thatthe at least one fiber ply is arranged adjacent to a layer of binder,ensures simple production of the grinding tool with high vibration andnoise damping in combination with a long life. As prepared, the at leastone fiber ply does not have any binder. On the one hand, the layer ofbinder arranged adjacent to the at least one fiber ply gives the mainbody the required strength. On the other hand, the at least one fiberply does not form a continuous or full-area bond with the binder, andtherefore the desired relative movement is achieved within the main bodyduring grinding. The layer of binder is preferably formed as a binderfilm. One layer of binder, in particular a binder film, is preferablyprovided between two fiber plies without binder. One fiber ply withoutbinder and one layer of binder, in particular a binder film, arepreferably provided alternately.

A method configured such that a supporting layer is arranged on the mainbody, ensures the production of the grinding tool with high vibrationand noise damping in combination with high cutting performance and along life. The supporting layer serves as an intermediate layer betweenthe main body and the abrasive layer. The supporting layer is formedaccording to the desired use. The supporting layer is formed, forexample, from a metallic material, a woven supporting fabric and/orpaper. In particular, the supporting layer is connected monolithicallyto the main body. The abrasive layer is secured on the supporting layeror on one surface of the supporting layer. The abrasive layer can bearranged or secured on the supporting layer before and/or after thesupporting layer is arranged on the main body.

A method configured such that the formation of the abrasive layer isperformed by electro-static application of abrasive particles, ensuressimple production of the grinding tool with the capacity for flexibleuse in combination with high cutting performance. The abrasive layercomprises an abrasive particle layer formed by the applied abrasiveparticles. By means of the electrostatic application of the abrasiveparticles, the abrasive particle layer is secured directly on the mainbody or on a supporting layer arranged on the main body. Electrostaticapplication makes possible a three-dimensional shape of the abrasivelayer in a simple way, thus allowing the grinding tool produced to beused flexibly. Furthermore, electrostatic application enables the mainbody or supporting layer to be re-coated or re-covered. Thus, afterconsumption of an abrasive layer, the remaining grinding tool can berenewed by electrostatic application of a new abrasive particle layerfor repeated use. By electrostatic coating, the abrasive particles areapplied directionally, in particular according to the course of theelectrostatic field lines. High cutting performance, especially whenusing abrasive particles with a geometrically determined shape, isthereby achieved. In particular, the abrasive particles are secured onthe main body or the supporting layer by means of an adhesive agent. Theformation of the abrasive layer is accomplished, in particular, bymultiple electrostatic applications of abrasive particles.

Further features, advantages and details of the invention will becomeapparent from the following description of a number of illustrativeembodiments.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a sectional view of a grinding tool according to a firstillustrative embodiment with a main body and an abrasive layer arrangedthereon,

FIG. 2 shows an enlarged sectional view of the grinding tool in FIG. 1to illustrate a structure of the main body with a binder and with fiberplies embedded in a partially movable manner in the binder,

FIG. 3 shows a schematic illustration of the production of the main bodyaccording to a first method,

FIG. 4 shows a schematic illustration of the production of the main bodyaccording to a second method,

FIG. 5 shows a schematic illustration of the production of the main bodyaccording to a third method,

FIG. 6 shows a schematic illustration of the production of the main bodyaccording to a fourth method,

FIG. 7 shows a schematic illustration of the electrostatic applicationof abrasive particles to the main body,

FIG. 8 shows a schematic sectional illustration of a grinding toolaccording to a second illustrative embodiment, and

FIG. 9 shows a schematic illustration of the production of the main bodyof the grinding tool in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first illustrative embodiment of the invention is described below withreference to FIGS. 1 to 7. A handheld grinding machine (not illustratedspecifically) is used in operation to drive a grinding tool 1 inrotation.

The grinding tool 1 is of disk-shaped design. The grinding tool 1comprises a main body 2 and an abrasive layer 3 arranged thereon. In aclamping region 4, the main body 2 has a circular opening 5 to receive adrive shaft of the grinding machine. The opening 5 defines an axis ofrotation 6 of the grinding tool 1. As an alternative to the opening 5,the grinding tool 1 can have a shaft.

The grinding tool 1 comprises a working region 7, which surrounds theclamping region 4 in a ring shape. In the working region 7, the abrasivelayer 3 is arranged on the main body 2. The working region 7 is dividedinto an inner region 8 and an outer region 9. The inner region 8 is ofannular design and surrounds the clamping region 4. In the inner region8, the surface of the main body 2 on which the abrasive layer 3 isarranged is of substantially level design. The outer region 9 is ofannular design and surrounds the inner region 8. In the outer region 9,the surface of the main body 2 on which the abrasive layer 3 is arrangedis of substantially curved design. In the outer region 9, the main body2 is curved relative to the axis of rotation 6 along a radial directionR and along a circumferential direction U. By virtue of the curvature ofthe main body 2, the abrasive layer 3 is formed in a correspondinglycurved and three-dimensional way.

The main body 2 comprises a number N of fiber plies, wherein thefollowing applies in general: 1≤N≤12, in particular 2≤N ≤10, and inparticular 4≤N≤8. The fiber plies are denoted individually by F₁, wherei denotes a running index for the individual fiber plies and depends onthe number N. By way of example, the grinding tool 1 illustrated in FIG.1 comprises four fiber plies, which are denoted individually by F₁ toF₄. The fiber plies F₁ to F₄ are illustrated only schematically inFIG. 1. The fiber plies F₁ to F₄ are designed as woven fabric and/ornon-crimp fabric.

The main body 2 comprises a binder B, in which the fiber plies F₁ to F₄are embedded in such a way that the fiber plies F₁ to F₄ are connectedpartially firmly to the binder B and are arranged in such a way as to bepartially movable relative to the binder B and relative to one another.To achieve this, a mass ms of the binder B to a mass m_(F) of the fiberplies F₁ to F₄ is relatively small. For a ratio M=m_(B)/m_(F) of themass ms of the binder B to the mass m_(F) of the fiber plies F₁ to F₄,the following applies: 1/25≤M≤½, in particular 1/20≤M≤⅓, in particular1/15≤M≤¼, and in particular 1/12≤M≤⅙. The binder B is an organicadhesive, in particular phenolic resin, epoxy resin and/or naturalrubber.

FIG. 2 illustrates the partially movable arrangement of the fiber pliesF₁ to F₄ in the binder B. The adjacent fiber plies F₁ and F₂ areillustrated by way of example in FIG. 2. The fiber plies F₁ to F₄ aredesigned as woven fabrics, for example, and each have a plurality ofweft yams S and warp yarns K extending transversely thereto. In FIG. 2,the weft yarns S₁ and the warp yarns K₁ of the first fiber ply F₁ andthe weft yarns S₂ and the warp yarns K₂ of the second fiber ply F₂ areillustrated. Owing to the relatively small quantity of binder B,connection-free regions V, in which the fiber plies F₁ to F₄ are notconnected by the binder B, are formed in the main body 2. In theseconnection-free regions V, the fiber plies F₁ to F₄ are movable inthemselves and relative to the binder B. The fiber plies F₁ to F₄embedded in the binder B are thus movable in themselves and/or relativeto one another in some regions. In the connection-free regions V, theweft yams S₁, S₂ and/or the warp yarns K₁, K₂ are movable relative toone another, for example. The connection-free regions V allow a relativemovement of the fiber plies F₁ to F₄ in some regions within the mainbody 2.

The abrasive layer 3 comprises abrasive particles 10 with ageometrically determined shape, which are secured on the main body 2 bymeans of an adhesive agent 11. The adhesive agent 11 is a resin, inparticular phenolic resin, for example. The abrasive particles 10 arearranged directionally relative to one another and relative to a surfaceof the main body 2. The abrasive particles 10 form an abrasive particlelayer 12. A top binding 13 and a top layer 14 are arranged on theabrasive particle layer 12 in the usual way. The top binding 13 and/orthe top layer 14 preferably have/has fillers with a grinding action.

By virtue of the fact that the fiber plies F₁ to F₄ allow a relativemovement in themselves and/or relative to one another, forces whicharise during grinding are absorbed by the main body 2, thereby ensuringhigh vibration and noise damping. The main body 2 nevertheless hassufficient stability and strength, and therefore the grinding tool 1 hasa long life. The main body 2 can be produced easily and in anygeometrical shape, and therefore the grinding tool 1 is flexible inapplication. The abrasive layer 3 is easy to apply to the main body 2shaped in the desired manner, and therefore the abrasive layer 3 ensureshigh cutting performance of the grinding tool 1.

The production of the main body 2 is described below:

A first production method is illustrated in FIG. 3. In the firstproduction method, the fiber plies F₁ to F₄ are prepared without binder.Layers of binder B are arranged between the fiber plies F₁ to F₄ thatare arranged one above the other. The layers of binder B are designed asbinder films. The fiber plies F₁ to F₄ and the layers of binder Barranged therebetween are then pressed against a main body form G undera pressure p and heated in such a way that the binder B becomes fluid.The binder B connects the fiber plies F₁ to F₄ in the manner described.The main body 2 is formed by cooling the binder B.

A second production method for the main body 2 is illustrated in FIG. 4.In the second production method, fiber plies F₁ and F₄ are preparedwithout binder B, and fiber plies F₂ and F₃ are prepared with binder B.Fiber plies F₂ and F₃ are each impregnated with the binder B on bothsides. The fiber plies F₁ to F₄ are arranged one above the other andpressed against the main body form G under a pressure p and heated insuch a way that the binder B becomes fluid. The binder B connects thefiber plies F₁ to F₄ in the manner described. The main body 2 is formedafter the cooling of the binder B.

A third production method for the main body 2 is illustrated in FIG. 5.In the third production method, the fiber plies F₁ to F₄ are impregnatedon one side with the binder B during preparation. The fiber plies F₁ toF₄ are arranged one above the other and pressed against the main bodyform G under a pressure p and heated in such a way that the binder Bbecomes fluid. The binder B connects the fiber plies F₁ to F₄ in themanner described. The main body 2 is formed after cooling 4.

A fourth production method for the main body 2 is illustrated in FIG. 6.In this production method, the prepared fiber plies F₁ to F₄ are eachprovided in some region or regions with the binder B on two sides. Thefiber plies F₁ to F₄ are impregnated with the binder B in some region orregions. The fiber plies F₁ to F₄ are arranged one above the other,pressed against the main body form G under a pressure p and heated insuch a way that the binder B becomes fluid. The binder B connects thefiber plies F₁ to F₄ in the manner described. After cooling, theconnected fiber plies F₁ to F₄ form the main body 2.

The production method and the fiber plies F₁ to F₄ prepared can becombined with one another in a desired manner.

The formation of the abrasive layer 3 on the main body 2 and theproduction of the grinding tool 1 are described below:

By means of an application device 15, the abrasive particles 10 areapplied electrostatically to the main body 2. The application device 15comprises a handling device 16 for handling and positioning the mainbody 2, a first electrode 17 and an associated second electrode 18 forgenerating an electrostatic field E, and a metering device 19 forfeeding the abrasive particles 10 to a conveyor 20.

The conveyor 20 comprises an endless conveyor belt 21, which istensioned by means of two deflection pulleys 22, 23. Deflection pulley22 is driven in rotation by means of an electric drive motor 24. A partof the conveyor belt 21 arranged above the deflection pulleys 22, 23 inrelation to the force of gravity F_(G) forms a conveying region 25,which extends in a horizontal x direction and a horizontal y direction.

The metering device 19 is arranged ahead of the electrodes 17, 18 in aconveying direction 26. The first electrode 17 is of plate-shaped designand is arranged below the upper part of the conveyor belt 21 and belowthe conveying region 25 in the direction of the force of gravity F_(G).In contrast, the second electrode 18 is arranged above the conveyor belt21 and the conveying region 25 in relation to the force of gravityF_(G). The second electrode 18 is thus spaced apart from the firstelectrode 17 in a vertical z direction, with the result that theconveying region 25 extends between the electrodes 17, 18. The secondelectrode 18 is secured on the handling device 16. The x, y and zdirections form a Cartesian coordinate system.

The second electrode 18 is shaped to match the main body 2. The mainbody 2 is held by means of the handling device 16 in such a way that thesecond electrode 18 rests substantially over the full area against arear side of the main body 2. The handling device 16 holds the main body2 mechanically and/or pneumatically, for example. An electric voltageU_(E), which is generated and can be set by means of a voltage source27, is applied between the first electrode 17 and the second electrode18.

The adhesive agent 11 is first of all applied on a surface facing awayfrom the second electrode 18, with the result that the adhesive agent 11arranged on the main body 2 forms a three-dimensionally shaped adhesionsurface. The adhesive agent 11 is applied manually, for example, or bymeans of the handling device 16. The surface of the main body 2 isdipped into the adhesive agent 11 by means of the handling device 16,for example.

The main body 2 is then positioned above the first electrode 17 in the zdirection by means of the handling device 16, with the result that theadhesion surface is arranged partially in the electrostatic field Ebetween the electrodes 17, 18. The field lines emanate vertically fromthe surface of the first electrode 17 and enter the surface of thesecond electrode 18 vertically, with the result that the field lines runsubstantially vertically through the adhesion surface.

By means of the conveying device 20, the abrasive particles 10 for theformation of the three-dimensionally shaped abrasive particle layer 12are transported into the electrostatic field E. For this purpose, themetering device 19 supplies the abrasive particles 10. The abrasiveparticles 10 are fed to the conveyor belt 21 and distributed thereon ina metered manner by means of the metering device 19. By means of theelectric drive motor 24, the conveyor belt 21 with the abrasiveparticles 10 arranged thereon is moved in the conveying direction 26,thus ensuring that the abrasive particles 10 are brought into theelectrostatic field E. The speed of transfer in the conveying direction26 can be set by means of the electric drive motor 24.

By means of the electrostatic field E, the abrasive particles 10 aremoved to the adhesive agent 11 and the adhesion surface counter to theforce of gravity F_(G), and are aligned along the field lines. When theabrasive particles 10 touch the adhesion surface, they remain stuckthere. By means of the adhering abrasive particles 10, the abrasiveparticle layer 12 is formed on the main body 2. In order to apply theabrasive particles 10 uniformly and homogeneously, the main body 2 isrotated about a central longitudinal axis 28 by means of the handlingdevice 16.

After the abrasive particle layer 12 has been fully applied to the mainbody 2, the main body 2 with the adhesive agent 11 and the abrasiveparticle layer 12 forms a semifinished product. The semifinished productis released by the handling device 16 and arranged in a heating device,where the adhesive agent 11 is cured. The top binding 13 and the toplayer 14 are then applied to the abrasive particle layer 12 in the usualway. In respect of further details and features of the grinding tool 1and of the electrostatic application of the abrasive particles 10,attention is drawn explicitly to WO 2018/149 483 A1, the contents ofwhich are incorporated by reference at this point.

A second illustrative embodiment of the invention is described belowwith reference to FIGS. 8 and 9. In contrast to the previousillustrative embodiment, the main body 2 comprises damping particles D.The damping particles D are natural rubber particles and/or foamparticles, for example. The damping particles D are incorporated intothe main body 2 during the production of the latter. The dampingparticles D form additional connection-free regions V and themselveshave noise- and vibration-damping properties.

The grinding tool 2 furthermore comprises a supporting layer 29, whichis connected to the main body 2 and provides a surface for thearrangement of the abrasive layer 2. The supporting layer 29 is composedof a metallic material. The supporting layer 29 is connectedmonolithically to the main body 2. For this purpose, the supportinglayer 29 is produced together with the main body 2. This is illustratedin FIG. 9. The supporting layer 29 is covered electrostatically withabrasive particles 10 in the manner described before and/or after beingconnected to the main body 2.

In respect of further aspects of the construction, production andoperation of the grinding tool 1, attention is drawn to the previousillustrative embodiment.

In general, the following applies:

The grinding tool 1 according to the invention does not have continuousor full-area bonding with the binder within the main body 2, andtherefore there are connection-free free spaces or regions within themain body 2, e.g. air inclusions. The main body 2 has a quantity ofbinder B such that, on the one hand, a relative movement is madepossible within the main body 2 but, on the other hand, the main body 2is sufficiently firm and does not delaminate during grinding. This isachieved by means of insular or fine wetting of the fiber plies F_(i).The free relative movement within the fiber plies F_(i) or therespective fiber ply F_(i) allows high vibration and noise damping. Byvirtue of the fiber plies F_(i) connected to one another by means of thebinder B and by virtue of the possible relative movement within therespective fiber ply F_(i), a construction of the main body 2 such thatthere are alternating hard and soft layers is achieved. An additionalrubber ply is not required to achieve high vibration and noise damping.The fiber plies F_(i) moving one inside the other make possible the highvibration and noise damping but ensure that there is no wrinkling Themain body 2 can be produced with any desired three-dimensional shape, inparticular by draping the fiber plies F_(i) and connecting the fiberplies F_(i) by means of the binder B.

The respective fiber ply F_(i) has a connection on both sides to thebinder B, thus ensuring that there is no delamination of the fiber pliesF. The binder B connects the individual fiber plies F_(i), which remaininherently flexible. The binder B is an elastomer, for example, therebyassisting the vibration and noise damping of the main body 2. The atleast one fiber ply F_(i) is padded, for example. The at least one fiberply F_(i) is coated, laminated, sheathed or silanized with the binder B,for example. The respective fiber ply F_(i) is designed as a wovenfabric or non-crimp fabric. The fiber plies F_(i) within the main body 2are designed as woven fabrics and/or non-crimp fabrics. The woven fabrichas a twill weave, for example. A twill weave ensures movement ormobility within the woven fabric and simplicity of draping. The fiberplies F_(i) are arranged as inner fiber plies and/or outer fiber pliesin the main body 2. The abrasive layer 3 can comprise an abrasiveparticle layer 12 or an abrasive fleece. The abrasive particle 10 is acoated ceramic particle, for example. The supporting layer 29 serves asan intermediate layer between the main body 2 and the abrasive layer 3.The supporting layer 29 can be designed as paper, film and/or wovenfabric. The supporting layer 29 is composed of a metallic material, forexample. Abrasive particle 10 is preferably applied directly to the mainbody 2 or the supporting layer 29.

1-20. (canceled)
 21. A grinding tool comprising a main body having abinder, at least one fiber ply embedded in the binder, and an abrasivelayer, wherein the at least one fiber ply is arranged in the binder in apartially movable manner.
 22. The grinding tool as claimed in claim 21,wherein each fiber ply comprises a plurality of yams that are embeddedin the binder in a partially movable manner relative to one another. 23.The grinding tool as claimed in claim 21, wherein the main bodycomprises a plurality of fiber plies that are embedded in the binder andare movable relative to one another in some region or regions.
 24. Thegrinding tool as claimed in claim 21, wherein the main body comprises aplurality of fiber plies having a plurality of yams, and the yams areembedded in the binder in a partially movable manner relative to oneanother.
 25. The grinding tool as claimed in claim 21, wherein the atleast one fiber ply comprises at least one of at least one woven fabricand at least one non-crimp fabric.
 26. The grinding tool as claimed inclaim 21, wherein the main body comprises a number N of fiber plies,wherein: 1≤N≤12.
 27. The grinding tool as claimed in claim 21, wherein,for a ratio M of a mass m_(B) of the binder to a mass m_(F) of the atleast one fiber ply, the following applies: 1/25≤M≤½.
 28. The grindingtool as claimed in claim 21, wherein the main body comprises dampingparticles.
 29. The grinding tool as claimed in claim 21, wherein thebinder is an organic adhesive.
 30. The grinding tool as claimed in claim21, wherein the main body is of curved design.
 31. The grinding tool asclaimed in claim 21, comprising a supporting layer, which is connectedto the main body and on which the abrasive layer is arranged.
 32. Thegrinding tool as claimed in claim 21, wherein the abrasive layer isshaped three-dimensionally.
 33. A method for producing a grinding toolhaving the following steps: preparing at least one fiber ply and abinder, producing a main body by heating and then cooling the binder,wherein the at least one fiber ply is arranged in a partially movablemanner in the binder after cooling, and forming an abrasive layer. 34.The method as claimed in claim 33, wherein a plurality of fiber pliesare used to produce the main body.
 35. The method as claimed in claim33, wherein the heating of the binder takes place under pressure. 36.The method as claimed in claim 33, wherein preparation takes place insuch a way that the at least one fiber ply is provided with the binderon one side.
 37. The method as claimed in claim 33, wherein preparationtakes place in such a way that the at least one fiber ply is providedwith the binder in one of some region and regions on two sides.
 38. Themethod as claimed in claim 33, wherein preparation takes place in such away that a first fiber ply without binder is arranged adjacent to asecond fiber ply provided with binder.
 39. The method as claimed inclaim 33, wherein preparation takes place in such a way that the atleast one fiber ply is arranged adjacent to a layer of binder.
 40. Themethod as claimed in claim 33, wherein a supporting layer is arranged onthe main body.
 41. The method as claimed in claim 33, wherein theformation of the abrasive layer is performed by electrostaticapplication of abrasive particles.